A library catalogue and a bibliography are distinct from each other as they serve different purposes. A bibliography is an organised list of documents compiled for some purpose. The purpose is usually to bring to the notice of the reader an exhaustive or select list of documents relevant to the pursuit of his enquiry or study. A bibliography may he of books such as Cumulative Book Index, or journal articles such as Indian Education Index (1947-1978) edited by K. G. Tyagi, 1980 or of doctoral theses and dissertations such as Bibliography of Doctoral Dissertations in India complied by Association of Indian Universities, New Delhi. The bibliography may be of documents published in a language such as Hindi Grantha Kosha 1976-1980 and 1981-1985, of publications of a country such as Indian National Bibliography. Details of varieties of bibliographies have been given in the Course BLIS-05. The bibliography may be on a particular subject or documents pertaining to a specific period of time, in one or more languages. A bibliography may either be comprehensive in its scope and coverage or selective.
These bibliographies cater to all the approaches of readers such as author, subject, and title and also may be annotated. Such bibliographies are generally prepared either by scholars or by technically qualified library staff. They may be prepared by individual libraries at local level to assist their users. In such cases, they comprise select list of items, which are of specific interest to the users. Bibliographies are expected to be authentic and are mostly used as reference tools in literature search. Preparation of bibliographies calls for scholarship and critical faculties of assessment and evaluation of documents, on the part of their compilers. The basic difference between a bibliography and a library catalogue is that a bibliography tells us what publication have been published but does not tell us where (in which library) these publications will be available for reading.
Bibliographies do not contain call numbers of books and names of libraries possessing those books. In order to consult the book, a reader has to consult a library catalogue which tells the reader, whether the required book is available in the library along with the call number of the document. This call number directs the reader to the hook on library shelves.
A library catalogue, however, records, describes and indexes the bibliographical resources of a particular library. Nonetheless, the printed catalogues of some of the biggest national libraries of the world such as the Library of Congress, The British Library, The National Library, Calcutta, serve as excellent bibliographical tools for literature search, reference and cataloguing work. The volume, variety and the quantity of materials built up in these national libraries of eminence and the scholarly and meticulous way the catalogue entries are prepared and presented, invest these catalogues with unquestionable authority as reference tools.
So, while a library catalogue is a key to a library's collection, a bibliography is merely a list of documents, comprehensive or selective in its scope and coverage, etc. and hence does not serve the functions of a library catalogue.
Very often, the terms 'catalogue' and 'index' are used synonymously. In other words, they are taken to mean one and the same thing but they are not. A catalogue, more particularly, a library catalogue is a record describing the documents acquired by a library, whereas an index provides access to any of bibliographical entries of the catalogue through author, subject or title index. In the context of a library catalogue, the generally accepted difference between a catalogue entry and index entry is that the former includes some descriptive specification of a document, whereas an index entry merely locates an author or a subject or title.